In general, a conventional circuit board for carrying and electrically connecting a plurality of electronic components substantially comprises circuit layers and dielectric layers that are stacked alternately. Each of the circuit layers are defined and formed by performing a patterning process on a conductive layer. Each of the dielectric layers is disposed between adjacent ones of the circuit layers for spacing apart the circuit layers. In addition, each of the stacked circuit layers may he electrically connected to another by a conductive via. Furthermore, various electronic components (such as active components or passive components) can be disposed on a surface of the circuit board, and electrical signal propagation is achieved by means of an internal circuit of the circuit board.
Due to miniaturization of many electronic products, the application of circuit boards rapidly increases; for example, circuit boards can be applied in flip phones and notebook computers. Hence, it is necessary to develop a combined circuit board combining a flexible circuit board and a rigid circuit board.